Flame arrestor



March 16, 1965 F. 1.. CORBIN 3,173,411

FLAME ARRESTOR Filed Oct. 22, 1962 2 Sheets-Sheet 1 INVENTOR. FLOYD L, Caps/7v March 16,1965 F. L. CORBIN FLAME ARRESTOR 2 Sheets-Sheet 2 Filed Oct. 22, 1962 Fl E5 F1 5+5 INVENTOR. Fwy/3 L Cope/7v United States Patent Ofiice 3,173,411 Patented Mar. 16, 1965 3,173,411 FLAME ARRESTUR Floyd L. Corbin, Tulsa, Okla, assignor to Enardo Manufacturing Company, Tulsa, Okla, a corporation of Oklahoma Filed Oct. 22, 1962, Ser. No. 232,147 4 Claims. (Cl. 12685) This invention relates to improvements in flame arrestors, and more particularly, but not by way of limitation, to a flame arrestor adapted to be secured to the air intake portion of a burner housing for the purpose of precluding accidental ignition of volatile gases in the atmosphere surrounding the housing.

It is known that a dangerous condition exists in the use of oil field heaters, reboilers, and other fired equipment associated with oil refineries, oil production fields, tank farms, pipelines and the like. This dangerous condition exists because fires frequently occur around fired equipment due to the accidential ignition of gas and vaporized petroleum products that may exist in a critical saturation range in the atmosphere immediately adjacent to the equipment. A leakage of petroleum, particularly the more volatile fractions of petroleum, and a contamination of the atmosphere with volatized petroleum vapors, as well as natural gases, may allow such equipment to be surrounded by a combustible mixture which is capable of ignition or explosion if subjected to a flame or a spark. A- flashback during the ignition or operation of fired equipment presents an open flame to this combustible atmosphere to initiate a fire or an explosion which results not only in a loss of the equipment itself, but also in the loss of other attendant costly equipment.

The present invention provides a flame arrestor adapted to be secured to the air intake portion of a burner housing and is so constructed as to preclude an accidental ignition of a combustible mixture surrounding the equipment. The device is constructed so as to allow a sufficient volume of air to pass through the arrestor to permit normal combustion within the burner housing, and yet provide a structure which precludes a flame from the burner propagating therethrough to ignite a combustible mixture enveloping the burner housing. This structure provides a plurality of passages through which air may pass to supply oxygen for the combustion within the burner housing, but which precludes formation of a passage sufficiently large to allow propagation of a flame therethrough.

It is an important object of this invention to provide a flame arrestor which will preclude accidental ignition of a combustible mixture surrounding fired equipment.

It is another object of this invention to provide a flame arrestor associated with fired equipment which will preclude flame being drawn through the arrestor to a point where it could ignite a combustible mixture surrounding the equipment.

It is yet another object of this invention to provide a flame arrestor to be associated with fire equipment which will allow sufficient air to be drawn therethrough to support combustion within the equipment and yet preclude an accidental flashback of flame.

It is a further object of this invention to provide a flame arrestor adapted to be secured to a burner housing which provides a plurality of passages through which sufilcient air may flow to support combustion within the burner housing and to construct all such passages of a size which will quench a flame being propagated therethrough.

It is still another object of this invention to provide a flame arrestor having a draft box surrounding the air vent thereof to preclude a vacuum being created on the interior of the arrestor thereby tending to produce a flame flashback.

It is a further object of this invention to provide a flame arrestor for fired equipment which will reduce danger to the operators of this equipment.

It is yet another object of this invention to provide a flame arrestor for fired equipment which may be easily and efficiently cleaned for proper operation.

It is yet a further object of this invention to provide a flame arrestor for fired equipment which is simple in construction, may be economically manufactured, and which will have a long service life.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

FIGURE 1 is a side view, partly in plan and partly in section, of a flame arrestor embodying the invention;

FIGURE 2 is an end view of the device shown in FIG. 1;

FIGURE 3 is a fragmentary longitudinal section, on an enlarged scale, of a portion of the arrestor shown in FIG. 1;

FIGURE 4 is a perspective view illustrating the flame arrestor secured to fired equipment;

FIGURE 5 is a side View, partly in plan and partly in section, of a flame arrestor cell adapted to be secured within the flame arrestor shown in FIG. 1;

FIGURE 6 is an end view of the cell shown in FIG. 5;

FIGURE 7 is a top view of a draft box adapted to be secured to the flame arrestor shown in FIG. 1; and,

FIGURE 8 is an end view of'the draft box shown in FIG. 7.

outer end of the cellrhousing 12 is closed by a cover 16- Which is secured to the housing 12 by a plurality of suitable latches 18. The housing 12 is provided with a plurality of aligned circumferentially spaced apertures 20 for a purpose which will be hereinafter set forth.

A flame arrestor cell 22, as seen most clearly in FIGS. 5 and 6, is particularly adapted for use in the flame arrestor 10. The flame arrestor cell is constructed by spirally winding a sheet 24 provided with a plurality of longitudinally extending corrugations and a flat sheet 26 around a central core 28. The inner and outer ends of the corrugated sheet 24 are tapered so that the configuration of the outer periphery of the cell 22 is substantially circular. The corrugations of the sheet or strip 24 and the flat sheet or strip 26 cooperate to provide a plurality of longitudinally extending passages 36, each of which has its length related to its cross sectional area in a manner to allow a volume of air to pass therethrough to support combustion within the burner housing 14 and to preclude propagation of a flame therethrough or a flame flashback by quenching the flame after it enters passages 30. For example, each passage 30 must be less than 0.142 inch in diameter when the cell 22 is four inches long to prevent the propagation of a flame when methane is present in the passages. The flat sheet 26 and the corrugated sheet 24 are composed of aluminum or the like, thereby allowing the heat of a flame entering the pasasges 30 to be conducted away to adjacent layers of the sheets.

A preferred method of constructing the cell 22 is to coat both sides of the sheet 26 with a suitable cement (not shown), such as an epoxy cement, as it is wound with the corrugated sheet 24 around the central core member 28. This cement secures the flat sheet 26 to the core member 28 and secures the corrugated sheet 24 to the sheet 26 at all points of contact therebetween, there- 131 lapped an extra turn around the periphery of the cell 22 to provide added protection to the corrugated strip. The corrugated sheet 24 and the fiat sheet 26, as stated, are preferably composed of a metal, such as aluminum, but the invention is not limited to the use of this material and another suitable fire-resistant good heat-conductive material could be used instead.

The flame arrestor cell 22 is preferably constructed to have an outer diameter slightly less than the inner diameter of the cell housing 12. The flame arrestor cell 22 is disposed within the cell housing 12 adjacent to its inner end which is secured to the burner housing 14. A pair of spaced annular gaskets or strips 32 are disposed between the outer periphery of the cell 22 and the inner periphery of the cell housing 12. The gaskets 32, which are preferably composed of asbestos, although not limited thereto, provide an airtight seal between the cell 22 and the cell housing 12 and preclude the formation of an air passage which would allow a flashback and an explosion. The aligned apertures 21) in the housing cell 12 communicate with an annular space 34 between the spaced gaskets 32 to permit a suitable slurry to be pumped therethrough which completely fills the space 34. A slurry suitable for such a purpose comprises a mixture of ground fire clay and water. An example of a slurry which has been successfully used is 20 mesh dry mill fire clay mixed with suflicient water to provide a slurry fluent enough to be pumped under pressure. As the slurry is pumped through the apertures to completely fill the annular space 34, suitable peg members or spikes 36 are driven through the apertures 20, as the pumping of the slurry continues, to close the apertures 20 and the penetrate into the flame arrestor cell 22. When the slurry has been allowed to dry, an annular band 37 of fire clay which completely fills the space 34 is interposed between th cell 22 and the cell housing 12. Although the particular material comprising the annular band 37 is recited as being fire clay, it is Within the scope of the invention to use another heat-resistant material in place of the fire clay. Such a material would have characteristics to allow it to completely fill the annular chamber 34 and to provide an eflicient fluid seal between the cell 22 and the housing 12. An example of another material which can be used is a suitable epoxy cement.

The annular gaskets 32 and the band of fire clay 37 cooperate to provide an efficient fluid seal between the outer periphery of the flame arrestor cell 22 and the inner periphery of the cell housing 12 to preclude the formation of a passage which would allow flame within the burner housing 14 propagating therethrough and igniting a combustible mixture surrounding the device 10. The peg members 36 which extend through the apertures 20 to penetrate the cell 22 secure it within the housing 12 and preclude longitudinal movement of the cell within the housing. The apertures 20 may be additionally sealed by an operation, such as welding or the like, thereby leaving a weld deposit 38 covering the aperture 20 of the outer periphery of the housing 12.

After a continued use of the flame arrestor 10, the longitudinally extending passages 30 may tend to become obstructed with dirt and grease or the like. The cell housing 12 may then be removed from the burner housing 14, the cover 16 removed from the housing 12 and a suitable cleaning fluid (not shown) passed through the passages 30 to remove the accumulated dirt or grease. The cleaning fluid may be passed through the passages 30 in any suitable manner, such as by immersing the housing 12 in a fluid or by passing a fluid through the passages 30 under pressure.

The inner end of the cell housing 12 and the outer end of the burner housing 14 are provided with outwardly extending flange portions 40 having a head 42 on the outer extremity thereof and inwardly extending annular flat portions 44. When it is desired to secure the housing 12 to the burner housing 14, an annular gasket 46,

preferably composed of asbestos but not limited thereto, is positioned between the abutting flat portions 44 of the housings in an abutting relationship. A split annular constrictor ring 48 of frusto-conical section with sidewalls 56 is positioned over the beads 42 to allow the sidewalls 5% to contact the outwardly extending flanges 40 of the burner housing 14 and the housing 12. The constrictor ring 48 is provided with a suitable latching mechanism 52, as seen in FIG. 2, which is preferably of a screw type so that a radial compressive force may be progressively applied by the constrictor ring 48 to the flange portions 41 to exert a wedging action against the annular beads 42 to clamp the flat portions 44 against the gasket 46, thereby providing an efficient fluid seal between the burner housing 14 and the cell housing 12. v I

If it is so desired, an annular ring 54 may be positioned inwardly of the flat portions 44 and in contact therewith; An annular ring 56 is secured to the ring 54 by a plu= rality of circumferentially spaced members 58 by weld ing or other securing means. The annular rings 54 and 56 cooperate with the flame arrestor cell 22 to position it within the cell housing 12 when the flame arrestor 10 is assembled. v

The lower portion of the outer end of the cell housing 12 is provided with a draft box 60 through which air may be drawn into the interior of the cell housing to support combustion within the burner housing 14. draft box 60 is provided with a box member 62 that is adapted to be secured to the cell housing 12 so as to errclose an air vent aperture 64 p'rovid'edin the lower por= tion of the outer end of the housing 12. The box memher 62 has a pair of opposed upwardly extending flanges 65 which are preferably secured to the inner periphery of the housing 12 to allow the box member 62 to extend through the aperture 64. The size of the box member 62 and the aperture 64 are so selected that when the box member 62 is secured around its upper portion to the housing 12 by welding' or other suitable means,- the aperture 64 will be entirely enclosedby the liox mem= ber 62 with the lower end of the box 62 then being the open air vent of the cell housing 12. A base plate 66 is spaced from the lower portion of the box member 62 and has secured thereto in a suitable manner, such as by welding or the like, a V-shaped baflle plate 68 which is also seemed to the box member 62. A plurality of fins 70, having apertures 72, extend upwardly from the base plate 66 and are secured to the bafile member 68 and the box member 62 in a suitable manner. A plurality of fins 74 having apertures 72 also extend up= wardly from the base plate and are secured only to the box member 62. The apertured fins 70 and 74 cooperate with the bafile plate 68 to allow a volume of air suflicient to support combustion within the burner housing '14 to be drawn through the open lower end of the box member 62. The fins 70 and 74 preclude a sudden gust of air around the cell housing 12 creating a vacuum within the cell housing 12 which would tend to draw a flame within the burner housing 14 through the flame arrestor cell 22 to a point where it could ignite an adjacent combustible mixture.

In use, a cell housing 12 having a flame arrestor cell 22 positioned therein is secured to a burner housing 14 in a manner hereinbefore set forth. It is apparent to a person skilled in the art that, as seen in FIG. 4, the burner housing 14 may be provided with a plurality of burners 76 and be adapted to be secured to the firetube of oil field treating or heating equipment (not shown).

From the foregoing, it is apparent that the present invention provides a flame arrestor wherein a flame ar-. restor cell 22 furnishes a plurality of longitudinally extending passages 30 which allow a volume of air suflicient to support combustion to pass through to burners 76 positioned within the burner housing 14. The flame arrestor cell 22 is so constructed to preclude any of the passages 30 being large enough in diameter in relation to length to allow a flame to be propagated therethrough, but are of such dimensions as to quench a flame from the burner housing 14 which might tend to flash back through the cell 22. The flame arrestor 22 is sealed within the cell housing 12 by the gaskets 24 and the annular band of fire clay 37 so as to preclude the formation of any passage around the outer periphery of the flame arrestor cell which would allow flame from the burner housing 14 to be propagated therethrough. The flame arrestor cell 22 is secured to the housing 12 by spikes or peg member 36 which permit the cell housing to be periodically removed from the burner housing 14 and for the flame arrestor cell 22 to be cleaned in an eflicient manner.

The air passing through the flame arrestor cell 22 initially enters the cell housing 12 through a novel draft box 60 which permits a suflicient volume of air to enter the housing and yet preclude a sudden gust of wind outside the housing creating a vacuum within the housing which would tend to quench the burners and tend to draw the flame within the burner housing through the flame arrestor cell 22 and ignite a combustible mixture which may surround the housing 12.

To further preclude possibility of an explosion, the cell housing 12 is secured to the burner housing 14 in a safe and efiicient manner which furnishes an airtight seal between the housings and preclude a combustible mixture leaking directly into the burner housing 14 where it would ignite. Thus, the present invention provides a flame arrestor which permits normal operation of fired equipment in an environment where a combustible mixture may surround the equipment and yet substantially precludes the possibility of a flashback or other accidental ignition of the combustible mixture which would result in a dangerous and costly explosion.

Changes may be made in the embodiment disclosed in the specification and drawings without departing from the spirit of the invention within the scope of the following claims as set forth.

I claim:

1. A flame arrestor for a burner housing having a burner disposed therein, comprising:

(a) a cell housing having two ends, one of which is adapted to be detachably secured to the burner housing;

(12) a removable cover member closing the other end of said cell housing;

(0) a flame arrestor cell having a plurality of longitudinally extending passages and being disposed in the cell housing, said passages being of a size for the passage of combustion-supporting air therethrough, but having a cross sectional area in relation to length to preclude the propagation of a flame therethrough;

(d) a pair of spaced annular strips disposed on the outer periphery of the cell and in contact with the cell housing;

(e) an annular band of heat-resistant material disposed between said strips and in contact with the cell housing and the cell and cooperating with said annular strips to seal the cell in the housing;

(f) means for securing the flame arrestor cell within the cell housing; and

(g) means provided in the cell housing for the ingress of air into the housing.

2. A flame arrestor for a burner housing having a burner disposed therein, comprising:

(a) a cell housing having two ends, one of which is adapted to be detachably secured to a burner housing having a burner disposed therein;

(b) a removable cover closing the other end of said cell housing;

(c) a flame arrestor cell disposed in the cell housing and provided with a plurality of longitudinally ex- 6 tending passages which allow air to be drawn therethrough to the burner housing and which preclude a flame from the burner housing being propagated therethrough;

(d) a pair of spaced annular strips disposed on the outer periphery of the cell and in contact with the cell housing;

(e) an annular band of fire-resistant material disposed between said strips and in :contact with the cell and the cell housing and cooperating with said annular strips to seal the cell in the housing;

(f) means to preclude longitudinal movement of the flame arrestor cell within the cell housing;

(g) the cell housing being provided with an aperture for receiving air therethrough; and

(h) baflie means secured to the housing around said aperture to allow an ingress of air therethrough and to preclude an air current of high velocity outside the housing from creating a vacuum within the housing.

3. A flame arrestor for a burner housing having a burner disposed therein, comprising:

(a) a cylindrical cell housing having two ends, one of which is adapted to be detachably secured toa burner housing having a burner disposed therein;

(b) a removable cover member closing the outer end of said cell housing;

(0) a cylindrical flame arrestor cell having a plurality of longitudinally extending passages and being disposed in the end of the cell housing adjacent to the burner housing;

(d) said passages having a cross sectional area which will permit sufficient air for operation of the burner to pass through, but EUCl1 passage having a length greater than its diameter so as to preclude flame from the burner passing therethrough;

(e) a pair of spaced annular strips disposed on the outer periphery of the cell and in contact with the cell housing;

(i) an annular band of fire clay disposed on the outer periphery of the housing between the strips and in contact with the inner periphery of the housing and the strips to seal the cell in the housing;

(g) a plurality of circumferentially spaced inwardly extending peg members which extend through the cell housing and the fire clay and penetrate into the cell structure thereby precluding longitudinal movement of the cell within the cell housing;

(h) the housing being provided with an aperture in the portion adjacent to its outer end for receiving air therethrough;

(i) and means secured to the housing around said aperture which allow an ingress of air therethrough but which preclude an air current of high velocity outside the housing from creating a vacuum within the housing and tending to draw flame from the burner through the flame arrestor cell.

4. A flame arrestor for a burner housing having a burner disposed therein, comprising:

(a) a cell housing having two open ends, one of which is adapted to be detachably secured to the furnace housing;

(b) a removable cover member closing the other end of said cell housing;

(0) a flame arrestor cell having a plurality of longitudinally extending passages of small cross sectional area and being disposed in the end of the housing adjacent to the furnace housing;

(d) a pair of spaced annular strips interposed between the cell and the inner periphery of the housing;

(e) an annular band of fire clay disposed between said strips and in contact with the housing and cell and coopenating with said annular strips to seal the cell in the housing;

(I) said housing being provided with a plurality of (g) an inwardly extending peg member positioned in each aperture and penetrating through the band of fire clay and into the cell structure to preclude longitudinal movement of the cell within the hous- (h) the housing being provided with an aperture in the portion adjacent to the outer end for receiving air therethrough;

(i) an open-ended box member secured to the housing around said aperture;

(j) a base plate spaced from the box member;

(k) a plurality of apertured fins attached to the base plate and to the box member; and

(l) a triangularly shaped bafiie member secured to the box member and to the base plate and cooperating with the apertured fins to preclude an air current of high velocity outside the housing creating a vacuum in the housing which would quench a flame within the furnace housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,896,286 Burns et a1 Feb. 7, 1933 2,572,445 Cannon et al Oct. 23, 1951 2,664,081 Moran Dec. 29, 1953 2,941,525 Harshfield June 21, 1960 3,079,242 Glasgow Feb. 26, 1963 

1. A FLAME ARRESTOR FOR A BURNER HOUSING HAVING A BURNER DISPOSED THEREIN, COMPRISING: (A) A CELL HOUSING HAVING ENDS, ONE OF WHICH IS ADAPTED TO BE DETACHABLY SECURED TO THE BURNER HOUSING; (B) A REMOVABLE COVER MEMBER CLOSING THE OTHER END OF SAID CELL HOUSING; (C) A FLAME ARRESTOR CELL HAVING A PLURALITY OF LONGITUDINALLY EXTENDING PASSAGES AND BEING DISPOSED IN THE CELL HOUSING, SAID PASSAGE BEING OF A SIZE FOR THE PASSAGE OF COMBUSTION-SUPPORTING AIR THERETHROUGH, BUT HAVING A CROSS SECTIONAL AREA IN RELATION TO LENGTH TO PRECLUDE THE PROPAGATION OF A FLAME THERETHROUGH; (D) A PAIR OF SPACED ANNULAR STRIPS DISPOSED ON THE OUTER PERIPHERY OF THE CELL AND IN CONTACT WITH THE CELL HOUSING; 